Directions:
Stand in place with feet shoulder width apart, and jump onto a box with either a weighted vest or holding a dumbbell. Step back down to land softly and safely, but remember to focus on going as fast as you can while maintaining proper form. 

REPS:
15 jumps as fast as you can in 1 minute, for 10 minutes

REST:
The amount of time remaining after you completed 15 jumps in the one minute

SETS:
2